Hearing proection


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Robbins290
May 3, 2012, 12:41 PM
I have a question. I use 33 db plugs with ear muffs over them when i shoot high powered rifles and shotguns. When i shoot my handguns, would just the plugs be enough? I shot mostly 9mm's and 45's.

Its unfortable to wear both with safety glasses as im running around doing tactical shooting

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Dr T
May 3, 2012, 12:59 PM
In my view, I feel that the double protection is more important with handguns than with rifles and shotguns. The muzzle is much closer to your ears.

The two loudest guns I own are a S&W 357 magnum with a 2.5" non-ported barrel and a Ruger Security 6 with a 6" non-ported barrel. For some reason, the Taurus 357 with the ported barrel does a better job of directing the noise away.

Also painfully loud are the T/C Contender with the 221, 357 magnum, and 44 magnum barrels (with full power loads). The Super Blackhawk is a bit easier.

I have only found rifles to merit the double ear protection when the shooting bench is concrete and under a metal roof. It is only really bad when the gun has a shorter barrel. For example, my pet load for my 30-06 (load data too hot to publish but safe in this gun) Ruger #1 RSI with a 20" barrel (not sticking over the end of the bench really rings (with a primary shock wave hitting the roof followed by a shock wave reflected off the concrete bench hitting the roof).

FourTeeFive
May 3, 2012, 01:07 PM
T/C Contenders can be insanely loud, especially in rifle calibers. Another famous one is the Ruger Super Blackhawk in .30 Carbine.

33 dB plugs should be fine with most guns. I find muffs get in the way with rifles. I do like plugs and muffs on an indoor range for when someone else brings out their .50 hand cannons.

brnmuenchow
May 3, 2012, 01:13 PM
That would be a judgment call. I would say that pistols tend to hurt my ears more than rifles. If shooting with just ear muffs hurt than I will suggest wearing both, otherwise it might be a little too cautious... like I said it's a judgment call.

FourTeeFive
May 3, 2012, 01:20 PM
Be sure to check the NRR. Even that doesn't tell the full story. Firearms produce an impulse sound and most noise reduction information is based on continuous use (working around noisy machinery, for example).

I have some custom-molded earplugs that are ok, but not great. I'm going to order a pair of these, which should work better:

http://aurisonics.com/store/index.php?main_page=product_info&cPath=144&products_id=100

SlowFuse
May 3, 2012, 01:30 PM
Are you indoors or outdoors? The only time I feel the need to double up is when I'm inside.

303tom
May 3, 2012, 01:33 PM
what ?????

Robbins290
May 3, 2012, 02:02 PM
Outdoors. In a wide open sand pit. I use both when im target shooting. It does not bother my ears when i shot tactaical. But i wanted to make sure im not goin damage my ears over time

mdauben
May 3, 2012, 03:39 PM
IMO you can't really have too much hearing protection when shooting guns. I always "double up" whether I'm shooting a .22 rifle in a sand pit, or a .44 magnum in an indoor range.

allaroundhunter
May 3, 2012, 03:49 PM
I only double up when I am indoors. Outdoors I am fine with just plugs.

Robbins290
May 3, 2012, 08:38 PM
thanks everyone

Serenity
May 3, 2012, 10:15 PM
It's better to use them and not need them than to need them and not use them.:D

hso
May 3, 2012, 10:28 PM
Wear both all the time when shooting.

Noise level charts (http://www.freehearingtest.com/hia_gunfirenoise.shtml) show increasing dB levels from pistols (152-164 dB) to rifles (155-170 dB). You certainly don't gain anything by reducing your hearing protection and put yourself at greater risk of permanent hearing damage.

Drail
May 3, 2012, 10:30 PM
Good plugs inserted properly should be enough. They should be slightly crushed and inserted far enough into your ear canal so that they can expand back and provide a good seal. The decibel noise reduction ratings are really pretty meaningless when applied to a gunshot impulse. But wear some kind of protection at all times, even if you're back behind the line while others are shooting. I use Peltor Shotgunner muffs most of the time unless I am shooting a long gun that has a stock that prevents me from getting a good cheek weld on the gun or if I am working all day at a match in really hot weather. The only time I have felt a need to "double up" was when working as a range officer and having to stand behind the guys with the .38 Super guns with compensators and very hot handloads. Those guys are nuts. As far as indoor ranges go I can't comment because I refuse to use indoor ranges. Just breathing the air in those places on a busy day will kill you.

hso
May 3, 2012, 10:46 PM
The decibel noise reduction ratings are really pretty meaningless when applied to a gunshot impulse.

What's your basis for that statement?
An NRR of 12 provides more protection than an NRR of 9, but less than 20. Their relative value provides a reasonable basis for selecting high vs. low NRR. If the threshold of damage from impulse noise is 140dB from a single shot, then reducing any 150-170 dB gunshot below 140 dB is more likely from the highest NRR plug and muff combination than something lower.

Drail
May 4, 2012, 12:07 AM
My basis is that the tests are geared towards a constant steady noise. Different manufacturers use different scales and pick the one that gives them the highest rating. Just like "wattage" ratings on amplifiers.

hso
May 4, 2012, 12:54 AM
NRR of a product is established by applying the ANSI test method. This is an EPA requirement for all manufacturers so the testing for NRR is consistent across products. NRR doesn't depend upon the spectrum of the sound. The NRR is based on the A scale because this scale corresponds to the response curve of the human ear and if you're going to measure for damage to hearing your measurement instruments don't need the broader B and C scales with their higher and lower frequencies that can't be heard/harmed. An NRR 30 plug is 10 dB more protective than an NRR 20 plug on the scale relevant to human hearing damage, the A scale. It would be the same difference for the C scale (not that it matters) because the calculation of attenuated sound for C is a constant 7 dB different from A so there'd still be 10 dB difference in the attenuation of a 30 and 20 dB device.

The threshold from damage for an instantaneous sound pressure level (impulse) is 130-140 dBA (the ACGIH and US Army use the higher value). All firearms produce this and higher (unless suppressed, subsonic, sprinkled with pixie dust, ...) noise when fired and represent a hazard to hearing for the majority of people (damn standard deviations).

SO, the difference between any two given hearing protectors is the same regardless of scale, the dBA scale was developed to allow noise measurements to be made that are relevant to human hearing and is therefore the most relevant for hearing protection, NRR isn't the best measure of protection since it depends so much upon how well the hearing protection device is fitted, but it is still a solid relative measure of the protective value of hearing protection devices.

Here's a "fun" read from INEL for the US Army's Combat Hearing Protectors.

FourTeeFive
May 4, 2012, 10:07 AM
The decibel noise reduction ratings are really pretty meaningless when applied to a gunshot impulse.

What's your basis for that statement?

An NRR of 12 provides more protection than an NRR of 9, but less than 20. Their relative value provides a reasonable basis for selecting high vs. low NRR. If the threshold of damage from impulse noise is 140dB from a single shot, then reducing any 150-170 dB gunshot below 140 dB is more likely from the highest NRR plug and muff combination than something lower.

Among others:

http://www.proplugs.com/protunes.shtml

Caution:For noise environments dominated by frequencies below 500Hz, the C-weighted environmental noise level should be used. Although hearing protectors can be recommended for protection against the harmful effects of impulsive noise, the Noise Reduction Rating (NRR) is based on the attenuation of continuous noise and may not be an accurate indicator of the protection attainable against impulsive noise such as gunfire.

Low-frequency energy can be extremely destructive to hearing. C-weighting is much more accurate to use for gunfire since it contains more low-frequency information. A-weighting is fine for continuous broadband noise such as the sound level within an aircraft. A-weighting actually starts to roll off within the speech bandwidth:

http://www.cross-spectrum.com/audio/newgifs/weighting.gif

Also, different sound level meters are used for impulse response measurement versus continuous measurement. The "fast" mode of a normal SLM is only a 125ms attack time. That is 1/8th of a second. Not nearly quick enough to catch the initial acoustic impact of a gunshot. Unless an impulse meter is used the energy will be averaged and the overall SPL will be displayed as a lower dB level.

All that said, yes, in general a higher NRR means a higher impulse response reduction. But not necessarily, and in some cases devices with a lower NRR will still provide a higher level of protection against impulse noise than another device with a higher NRR. That was my point.

B!ngo
May 4, 2012, 11:47 PM
Frankly, it isn't completely known what the long-term cumulative effects of your type of shooting and the associated noise will be on your hearing. Too many variables, not enough long-term data, and all the rest.
Surely people accept that insufficient protection surely yields short and long-term impact on hearing and creates other associated and often permanent symptoms. Where the accumulated sound pressure function intersects the zero line of 'no effect' is impossible to completely compute, but I suspect does not actually exist.
When you're younger, it's fundamentally hard to imagine 'long-term' no less the cumulative effects of something as seemingly benign as loud noises. But it is a serious thing and I would strongly recommend that you double up always and bear with the occasional discomfort.
B

Serenity
May 5, 2012, 01:10 AM
A quick rant: my son said his high school friend's hearing is messed up and muffled sounding because he was shooting with inadequate (or no) protection. They are SIXTEEN. :cuss:

hso
May 5, 2012, 01:23 AM
If you want to use dBC instead subtract 7dB from the NRR. Then an NRR 30 attenuates 23 dBC and an NRR 20 attenuates 13dBC. The relationships between the protection don't change. If you want to attenuate low frequency sound add muffs on top of plugs (which we always recommend) and the muffs work on the lower frequency range better and you don't have to drop the 7dB for the C weighted noise measurement. Remember that when calculating NRR you simply add 5 dB for stacking muffs on plugs instead of NRR plugs+NRR muffs because they attenuate different frequencies better.

You have to keep in mind that the A weighting and the C rating are for the measurement of the sound and not the sound itself. The sound pressure level at different frequencies are what is out there. The A and C weighted measurements are how you measure them. Picture vs. terrane.

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